#include <thrust/functional.h>
#include <thrust/set_operations.h>
#include <thrust/sort.h>

#include <unittest/unittest.h>

template <typename Vector>
void TestSetDifferenceDescendingSimple()
{
  using T        = typename Vector::value_type;
  using Iterator = typename Vector::iterator;

  Vector a{5, 4, 2, 0}, b{6, 4, 3, 3, 0};

  Vector ref{5, 2};
  Vector result(2);

  Iterator end =
    thrust::set_difference(a.begin(), a.end(), b.begin(), b.end(), result.begin(), ::cuda::std::greater<T>());

  ASSERT_EQUAL_QUIET(result.end(), end);
  ASSERT_EQUAL(ref, result);
}
DECLARE_VECTOR_UNITTEST(TestSetDifferenceDescendingSimple);

template <typename T>
void TestSetDifferenceDescending(const size_t n)
{
  thrust::host_vector<T> temp = unittest::random_integers<T>(2 * n);
  thrust::host_vector<T> h_a(temp.begin(), temp.begin() + n);
  thrust::host_vector<T> h_b(temp.begin() + n, temp.end());

  thrust::sort(h_a.begin(), h_a.end(), ::cuda::std::greater<T>());
  thrust::sort(h_b.begin(), h_b.end(), ::cuda::std::greater<T>());

  thrust::device_vector<T> d_a = h_a;
  thrust::device_vector<T> d_b = h_b;

  thrust::host_vector<T> h_result(n);
  thrust::device_vector<T> d_result(n);

  typename thrust::host_vector<T>::iterator h_end;
  typename thrust::device_vector<T>::iterator d_end;

  h_end =
    thrust::set_difference(h_a.begin(), h_a.end(), h_b.begin(), h_b.end(), h_result.begin(), ::cuda::std::greater<T>());
  h_result.resize(h_end - h_result.begin());

  d_end =
    thrust::set_difference(d_a.begin(), d_a.end(), d_b.begin(), d_b.end(), d_result.begin(), ::cuda::std::greater<T>());

  d_result.resize(d_end - d_result.begin());

  ASSERT_EQUAL(h_result, d_result);
}
DECLARE_VARIABLE_UNITTEST(TestSetDifferenceDescending);
